But there are also some high-end projectors that use motorized focus, so they don't have a focus ring. You can adjust the focus through the "Focus" button on the projector panel or on the remote control, such as Epson projectors whose models start with EB-Z, EB-B, CB-Z
Yes, you can adjust the lens to make the screen clear. But if it doesn't work after you have adjusted it rightly, actually, there are other reasons why your projection screen will be blurry, such as:
1. The distance between the projector and the screen.
2. "Keystone" adjustment will degrade the projected image quality. It is recommended that you minimize the tilt angle of the projector up and down and left and right to minimize the effect of keystone distortion.
3. There is dust or stains on the surface of the projector lens. Gently wipe the lens with a commercially available soft cloth or lens tissue used to clean glass;
4. The condensation formed on the lens surface will affect the picture quality. When the ambient temperature changes, condensation will occur, please leave the projector for one to two hours before using it.